What is COVID-19? 

     

     The novel COVID-19 virus that is currently affecting people all over the world is part of a class of viruses called coronaviruses. Similar viruses in this family include Severe Acute Respiratory Syndrome (SARS) and Middle East Respiratory Syndrome (MERS), both of which caused epidemics in the past twenty years.

 

     A unique feature of COVID-19 is that it targets lower airways, shown by upper respiratory tract symptoms like rhinorrhoea, sneezing, and sore throat. An infiltration into the upper lobe of the lung is associated with increasing dyspnea with hypoxemia [2]. The most common symptoms are fever, cough, fatigue, pneumonia, headache, diarrhea, hemoptysis, and dyspnea. There is currently no antiviral treatment that has been proven effective, so most individuals rely on symptomatic treatment and supportive care [1].  

The estimate R0, or the expected number of cases produced from one person in a population susceptible to infection for is 2.2 [3]. Real time and reverse transcription PCR were used to characterize coronavirus; the current SARS- CoV-2 shares 79% of its genome with SARS-CoV, but is much more transmissible. The means of infection of SARS-CoVs is by entering the cell through the ACE2 receptor; SARS-CoV-2 infects the lower airways first and binds to the ACE2 on the alveolar epithelial cells, inducing inflammatory cytokines which inflicts damage onto organs [3]. The cases of SARS-CoV-2 increase exponentially, with a report of an epidemic doubling time of 1.8d according to modeling studies [3]. The mean incubation period, the time between moment of exposure to infectious agent and emergence of symptoms, is estimated to have a median of 4.75 days [5].

     

      Any virus cannot replicate on its own, and thus needs a host cell in order to do so; often times cytopathic effects, or changes in the biochemical and structural elements of the host cell can cause damages, and some cells may even burst through lysis or program their own death through apoptosis-- this releases all the progeny virions. A virus attaches to a cell through a specific receptor site on the host cell membrane, through glycoproteins in the viral envelope or proteins in the viral capsid. Viruses can have genomes in two forms: RNA or DNA. DNA viruses use the host proteins and enzymes to replicate its DNA, and transcribe it to mRNA that eventually translates into viral protein synthesis. On the other hand, RNA viruses use RNA core for synthesis of viral mRNA and proteins. If viral cells are missing necessary enzymes in the host cell, the viral genes supply information to directly synthesize missing proteins; specifically, retroviruses reverse transcribe their RNA into DNA which then becomes incorporated into the host genome. The last stage of viral replication is releasing the newly formed virions into the host organisms, allowing the virus to spread to adjacent cells to repeat the same cycle [4]. While more epidemiological information through testing and PCR samples are required to understand the quantitative asymptomatic transmission rates, there is evidence that asymptomatic patients infected with SARS-CoV-2 can actively spread the virus. The lack of symptom presentation by asymptomatic individuals poses difficulties in monitoring and identifying asymptomatic patients because they are easily neglected in epidemic prevention.

 

Is there a cure?

     

      Due to the unknown nature of the COVID-19 virus, personal protective equipment, or PPE, is crucial for health care workers who are being exposed to patients with the virus. PPE works to block transmission of the virus through various means of transmission, including droplet, airborne, and transdermal. All PPE must be correctly donned and doffed to limit the amount of contamination and transfer of the virus onto surfaces and other areas that might be used after an interaction with a patient. The most useful way to protect oneself is to use hand-washing and contact isolation gear/PPE for viral control. This is why it is so important to study PPE and preparedness of PPE. There is no current vaccine nor cure for the COVID-19 virus, and thus PPE, has become the main means in combating the virus. With PPE being the only means for health care providers to protect themselves from the virus, if supplies are limited, healthcare workers themselves are put at risk when they treat patients without proper protection. Additionally, since there are various routes of transmission, the means of infection is important to understanding PPE’s role/importance in preventing it. The rapid transmission from infected individuals as well as the ability of asymptomatic individuals to spread the virus without epidemic tracking also highlights the importance and reconsideration of the paradigm on the benefits and costs of mask-wearing for the greater public as well.

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